Electric motor/generator dynamometers are a specialized type of adjustable-speed drive or roller used for measuring force, moment of force (torque), or power. For example, the power produced by an engine, motor or other rotating prime mover can be calculated by simultaneously measuring torque and rotational speed (RPM).
An absorption/driver roller may be driven by, for example, either an alternating current (AC) motor or a direct current (DC) motor. Either an AC motor or a DC motor may operate as a generator which drives the engine being tested. When equipped with appropriate control features, electric motor/generator dynamometers may be configured as universal dynamometers. More specifically, in engine testing, a universal dynamometer may not only absorb and measure the power of the engine, but it may also drive the engine for measuring friction, pumping losses and other factors.
The present device relates to a miniature dynamometer which may easily and quickly demonstrate to students, auto-builders and others the techniques used in measuring engine forces and horsepower. The present device is especially suitable for testing the force of a miniature car and then scaling the results to determine an approximate force for a full sized vehicle. The present dynamometer utilizes DC motors/generators on each end of a roller upon which car tires rotate to drive the roller. In an alternative embodiment, the universal dynamometer may be aided by the roller motor/generators to simulate up and down hill conditions. The motor/generator bearings of the device may also act as the roller bearings. The revolutions per minute (RPM) and circumference of the roller may then be used to, for example, calculate the actual miles per hour of a miniature car driving on the roller. The car is scaled down to match the miniature size of the present dynamometer. The miles per hour displayed on the meter may then be multiplied up to emulate actual miles per hour of a full-sized car.
The present universal dynamometer utilizes a beam of light sent to a receiving unit which in turn measures the light intensity of the beam and produces an electrical output proportional to the intensity of the light beam. A rotating roller of the device is designed to block or reflect the beam of light which, in turn, produces a pulse train which may be used to later calculate the RPM of the roller. More specifically, the rotating roller produces pulses at a frequency which is ultimately converted into an actual miles per hour of the miniature car.
A light-emitting diode (LED) is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting. Introduced as a practical electronic component in 1962, early LEDs emitted low-intensity red light, but modern versions are available across the visible, ultraviolet and infrared wavelengths, with very high brightness.
The present miniature universal dynamometer educational tool allows for a safe and fun teaching device for students and industrial engine designers. The device may be used to study engine design and horsepower without the dangers often associated with working with full-sized vehicles and dynamometers.
There are mechanical products to measure horsepower such as dyno systems which include bike dynes, rolling road dynes (auto, kart, motorcycle or truck), and sled track-dynos. However, these devices are used to measure actual full-sized vehicles. Some teaching aids currently being sold which emulate the complex interactions of forces in the real world by electric motors are large, expensive, and dangerous. Diagrams, videos and teaching aids are also available which explain horsepower measurements in a virtual environment, but these devices typically lack the physical interaction with real variables such as wind resistance, uphill, downhill, and battery drain. To completely understand the complexity of an electric engine powered vehicle, a teaching aid is required which emulates the mixing of road conditions and drain on engine power source. The present device utilizes hardware along with software (virtual) test equipment to allow a student to fully grasp real life engine principles. The students learn by acquiring measurements obtained in the present system and may alter the system to test for various elements, such as, unique environmental and road conditions.
Attempts have been made to produce an efficient universal dynamometer, as demonstrated in U.S. Pat. No. 6,247,357 to Yamamoto which provides for a “test apparatus in the form of dynamometers which is widely used for testing motor vehicles in place. Since the test vehicles are not moving over a road bed, the dynamometer must simulate certain forces normally associated with actual vehicle operation. These parameters include forces associated with inertia (related to the mass or weight of the vehicle) and road load forces (related to the velocity of the vehicle). The vehicle engine (or its braking system) must overcome inertial forces in order to accelerate or decelerate the vehicle. In addition, the engine must overcome breakaway frictional and rolling frictional forces (i.e., road/tire friction) as well as windage forces (i.e., drag forces caused by air passing over the vehicle). These latter forces are commonly referred to as road load (RL) forces and may be represented by a formula:”
Attempts have also been made to utilize a USB computer connection to determine force as provided by in U.S. Pat. No. 6,282,469 to Rogers which provides “a multi-point serial link protocol, such as USB, is used to transfer vehicle diagnostic information back and forth between vehicle diagnostic sensors and a host computer. Multiple distinct vehicle servicing applications may be added to or removed from the service bay without requiring substantial software changes or revisions. The amount of vehicle diagnostic hardware is also minimized. The multi-point serial link may originate in the vehicle's on-board computer, allowing the vehicle itself to function as a data hub for the diagnostic automotive service sensors.”
Further, U.S. Pat. No. 6,457,351, also to Yamamoto, demonstrates the measuring of the force of electric motor vehicles wherein “a hybrid electric vehicle is placed in a running condition on a chassis dynamometer, a vehicle-end data is acquired by access to sensors in the vehicle, a dynamometer-end data is acquired by measurements at the chassis dynamometer, and the vehicle-end data and the dynamometer-end data are analyzed for inspections of drive and control systems of the vehicle.
These devices and patents fail to disclose a miniature dynamometer education tool and system which may easily, quickly and safely act as a teaching tool for students, auto-designers and others to learn and test simulated real world forces through the use of miniature or scaled down vehicles. Further, these devices and patents fail to disclose a device and system which has road load forces which may be used to test scaled-down vehicles and which may be used to demonstrate the workings of a fully electric miniature vehicle under various real world conditions.